Here are the four throws that I'm making a part of my April Grappling Gameplan. We don't work takedowns a lot, and Rodrigo is sure to show us his own. But these four encompass the four main situations: two leg throws, two leg hooks or trips, one inside and one outside each.
--uchi mata ("inside thigh sweep")
--harai goshi ("outside thigh sweep")
--ko soto gari ("outside leg hook")
--ko uchi gari ("inside leg hook")
The hook on the ko uchi gari isn't very good in these examples. But rest assured that there is an inside-to-outside sweep that initiates the takdown.
